import 'package:flutter/material.dart';

class Demo1 extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return Demo1State();
  }
}

class Demo1State extends State<Demo1> {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      body: new Container(
        color: Colors.green,
        child: new Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            new Text('Column 交叉轴默认方向为从左到右'),
            new Container(
              margin: EdgeInsets.only(top: 20.0),
              width: 60.0,
              height: 60.0,
              decoration: BoxDecoration(
                color: Colors.red
              ),
            ),
            new Container(
              margin: EdgeInsets.only(top: 20.0),
              width: 120.0,
              height: 60.0,
              decoration: BoxDecoration(
                color: Colors.red
              ),
            ),
            new Container(
              margin: EdgeInsets.only(top: 20.0),
              width: 100.0,
              height: 60.0,
              decoration: BoxDecoration(
                color: Colors.red
              ),
            ),
          ],
        ),
      ),
    );
  }
}